ARP 256-4002 Cylinder Head Stud Kit Pro Series Chrome Moly - 8740

The ARP 256-4002 Pro Series head stud kit delivers professional-grade cylinder head clamping force for high-performance and racing engines. Manufactured from premium 8740 chrome moly steel and heat-treated to 200,000 psi tensile strength, these studs provide superior reliability over standard head bolts in demanding applications.

Key Features:

• 8740 chrome moly alloy construction rated at 200,000 psi tensile strength
• Vertical rack heat-treatment ensures complete and consistent heat penetration
• Centerless ground after heat-treat for exceptional concentricity and straightness
• Threads rolled after heat-treatment for 10x better fatigue strength
• Hex head design for secure installation and removal
• Undercut shorter studs equalize stretch for consistent clamping force
• Includes hardened parallel-ground washers for even load distribution
• Precise manufacturing tolerances ensure proper gasket and head alignment

Performance Benefits:

ARP Pro Series studs offer significant advantages over standard head bolts. The stud design eliminates torsional loading during installation, as torque is applied only to the nut rather than twisting the fastener itself. This results in more accurate and consistent clamping force. The undercut design on shorter studs compensates for head gasket compression, helping prevent blown gaskets and maintaining optimal cylinder seal. The precision centerless grinding process ensures cylinder heads and gaskets align perfectly during assembly, critical for racing engines that require frequent servicing.

Installation Notes:

Install studs finger-tight in a relaxed mode—never force them in with a jammed nut. When torquing, the stud stretches only on the vertical axis, providing superior clamping characteristics. Always re-torque after initial engine run-in to compensate for head gasket compression.

Each stud is marked with the ARP stamp as assurance of quality and is manufactured to exacting tolerances that meet ARP's zero-defect, zero-failure quality standard. Trusted by professional engine builders across all forms of motorsports.